Radio communication and GPS navigation device

ABSTRACT

A navigation device configured to connect to any type of communication device, such as a two-way radio or a cellular phone. The navigation device includes a LCD display and a user input device. The navigation device displays on the LCD the relative distance and direction of other navigation devices relative to the navigation device, as well as the speed, distance traveled, current location, altitude, temperature of the other navigation devices. Also, the user interface allows the user to scroll through different menu options and display options of the LCD. The navigation device is additionally configured to send text messages to other navigation devices. The navigation device transmits three NMEA sentences allowing text messages, waypoint names and locations, speed, course, direction and altitude to be sent between navigation devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. §119(e)of U.S. Provisional Application No. 60/963,661, entitled “Hand held GPSfield unit with speaker microphone capability that connects to any twoway radio transceiver providing location information to other users ofthe combination GPS microphone unit as well as a PC or laptop connectedto another transceiver with connection to Google earth or other softwareapplication,” filed Aug. 4, 2007, which is hereby incorporated byreference herein.

FIELD OF THE INVENTION

This invention relates in general to Global Positioning Systems (GPS)and communications, and more specifically to GPS information transmittedover communications systems.

BACKGROUND

GPS portable devices are used by hikers, motorists, safety and militarypersonnel, hunters and many others who may wish to know the exactlocation of their current position. A GPS device receives positionalsignals from a number of different satellites surrounding the Earth anduses this information to calculate its position. After the location hasbeen determined, the location is illustrated to the user typicallythrough a display. Some GPS devices also give the user the ability tostore his location and track his progress by viewing the display. Thisdisplay may simply give the coordinates to the user of his currentlocation, or may be more sophisticated and indicate on an electronic maphis location.

Presently there are a number of wireless communication devices thatallow users to communicate across varying distances. For example, cellphones, two-way radios, internet-ready computers and portableelectronics allow one user to communicate to another, either throughspeech or electronic messages. This communication ability is vital forsome people, such as fire rescue personnel, and merely a convenience toothers such as old friends who want to catch-up. As GPS data has becomemore popular, GPS devices have been incorporated into many types ofcommunication devices. For example, some cell-phones also include a GPSreceiver allowing the user to locate his own position.

The National Marine Electronics Association (NMEA) has established astandard to transmit location data between GPS devices. This standard isa NMEA sentence and is a self-contained line data. In accordance withNMEA protocol a transceiver will transmit all sentences it is programmedwith to a receiver and the receiver selects only the sentences it isprogrammed to receive. In order for a receiver to read a particularsentence, the beginning of each sentence includes a prefix defining asentence type and how the sentence should be interpreted. The currentNMEA sentences transmit location data using latitude and longitudecoordinates represented by degrees and minutes. Along with the locationdata is a user identification number that indicates what user thelocation data represents. The NMEA standards currently limit eachsentence to 82 characters. Additionally, the NMEA transmission does notallow for a receiving device to request data be resent or indicate backto the transceiver that the sentence was read correctly. One limitationof the current NMEA sentences is that, in addition to lengthlimitations, the data types are also limited. For example, current NMEAsentences only send location data and short identification numbers.Additionally, due to the current format, NMEA sentences do not allow fora user to transmit both location and user identification in the samesentence along with any other information.

There are a few GPS integrated communication devices able to send aunit's location to another device or user through a transceiver thattransmits NMEA sentences to the receiver. For example, a GPS devicecombined with a mobile radio data modem provides the user's locationdata to a computer located elsewhere. However, this system requires anexpensive interface to operate, such as a digital radio interfaceconnected to a computer and running a software application and thus islimited to commercial users. In another example, a GPS device isintegrated with a non-licensed personal radio, such as a“walkie-talkie.” These devices only have a limited radio range, makingthem unsuitable for non-recreational activities. In addition to thesetwo examples, there are other limitations. For example, multiple userscannot track each other using the GPS communication devices, only twousers with the same device are able to have each other's locationsdisplayed. Additionally, the transmission ranges are eitherprohibitively expensive for the average consumer or are so limited inrange to be not useful for anything other than casual recreationactivities. Finally, the devices are not able to transmit meetingpoints, waypoints or other information to other users nor allow eachuser to track his path, speed and estimated time of arrival to themeeting point. These are significant limitations as coordinates that aretransmitted vocally to other users may be confused, mistaken or in themilitary context may be intercepted or overheard by enemy forces.Additionally, as only a limited amount of information is provided to theusers, planning, meeting and organizing is much more difficult.

SUMMARY

One embodiment of the invention includes a GPS unit with the capabilityto connect to any type of communication device, thus allowingcommunication over any conventional two way radio or digital networkwithout specialized equipment. The GPS unit itself may include a GPSreceiver, microphone, speaker, microprocessor, push-to-talk function(PTT), liquid crystal display (LCD) and a joystick or other similarinput device. These features allow the user to read from and interactwith the device and communicate with other users. The GPS unit uses thecommunication device to transmit and receive data to and from otherusers. One type of data transmitted is travel information, such as eachuser's location, direction, temperature, speed, altitude and time todestination. Each unit is able to see the travel information for eachgroup of users as well as each user separately. Additionally the unitdisplays the relative location of each unit compared with itself on theLCD, giving the user a pictorial illustration of each unit's location.Each user is also able to mark waypoint locations on his display andtransmit the exact locations to all other units. Furthermore, users ofdifferent units are able to send text messages to each other, regardlessof the type of communication devices being used.

The GPS location data and other information transmitted via thecommunication device may be formatted in a variety of NMEA sentences.The NMEA sentences transmitted and received may include all prior NMEAsentences as well as three novel sentences. These NMEA sentences includethe user's identification number or name in addition to the otherinformation included in each sentence. The first sentence transmits theuser identification, location, travel speed, temperature, course andaltitude in a single sentence. The second sentence transmits textmessages and the user identification of the sender to other users. Thethird sentence allows a user to send or receive waypoints from otherusers, including the direct coordinates selected through the LCD input.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a front view of a GPS unit connected to a two-wayradio transceiver.

FIG. 1 a illustrates a front view of a GPS unit connected to a cellphone.

FIG. 2 illustrates a perspective view of the GPS unit.

FIG. 3 illustrates a block diagram of the GPS unit.

FIG. 4 illustrates a LCD main menu displayed as on the LCD screen of theGPS unit.

FIG. 4 a illustrates a flow chart of a menu hierarchy of the main menuof FIG. 4.

FIG. 4 b illustrates a text message composition screen displayed on theLCD screen of the GPS unit.

FIG. 5 is a diagram illustrating GPS units connected to communicationdevices and transmitting information between units and to a computerover a radio network.

FIG. 6 is a diagram illustrating the GPS units connected to cell phonescommunicating over a cellular network.

FIG. 7 is a diagram illustrating multiple GPS units connected tocommunication devices using the group list function.

DETAILED DESCRIPTION

Described herein are various embodiments of a GPS unit for use with avariety of communication devices. The GPS unit connects to any type ofcommunication device, for example a two-way radio, cell phone, computeror personal digital assistant with broadband access or a digital modem.The unit allows a user to track his location and other travelinformation, track other users' locations and their travel informationand communicate to other users. The GPS unit may include a microphone,speaker, GPS receiver, push-to-talk button (PTT), power button, memory,microprocessor, compass, clock, temperature sensor, altimeter, battery,function key, universal serial bus (USB) port, radio interface port,joystick or any combination of the above elements. Additionally, the GPSmay be combined with other functions and elements not listed. Themicroprocessor receives inputs from the user, clock, compass, GPSreceiver, memory and other internal and external signals. Themicroprocessor processes the data, performs calculations and providesoutputs to a LCD, USB and radio interfaces as well as any other elementrequiring information from the microprocessor.

A LCD main menu screen displays a number of different icons andinformation. The informational icons may include a battery powerindicator, GPS status, local time, calendar, temperature, altitude,message received, backlight on, and track mode. The LCD functional iconsmay be used to access the different functions of the unit. From the mainscreen the user may choose between different functional icons, such asfinder, group list, waypoints, unit data, tracks, compass, messaging,satellite signal strength, and tools. A finder icon allows the user tolocate a specific unit showing that unit's distance, bearing andestimated time of arrival relative to the user selecting the specificremote unit as well as the tracks, location, temperature, altitude,heading and speed and area previously covered by the remote unit.Similarly, a group icon allows the user to select a unit or group ofunits, tracked collectively, and receive all the relevant informationsuch as direction, speed, temperature, elevation, location, etc. for theentire group or specific units within the group. Under a waypoints iconthe user can add, view, save, send or delete waypoints. Saved waypointsby the user may be transmitted to other field units electronically,avoiding the need to verbally transmit the waypoint characteristics,which takes both time over a radio channel as well as possibly resultingin errors (e.g., radio transmission is garbled, user incorrectly writesdown the waypoint information, etc.). A unit data icon shows the time,data, altitude, speed, source, location, maximum speed, temperature,average speed and distance traveled by the user. A tracks icon allowsthe user to start, stop and erase a travel course. A compass iconillustrates the current directional heading. A messaging icon allows theuser to send and receive text messages, the user is able to compose amessage by a virtual keyboard that appears on the screen when thatfunction is selected. A satellite signal strength icon illustrates theunit's location, time, date, altitude, speed, and GPS fix. Finally, atools icon supplies all the system's data and settings and allows a userto modify certain settings, displays and functions of the GPS radiomicrophone unit.

The GPS unit may be connected to any type of communications device thatincludes an audio input and a sound output. For example, a two-wayradio, cell phone, digital radio, modem, computer or personal digitalassistant with broadband or other internet access. The GPS unit connectsto the communication device wirelessly or through a connection cord.Once the unit is connected to the device, the user may then use theunit, versus the communication device, to transmit and receive audio andother communication signals. For example, when connected to a two-wayradio, a user uses the GPS radio microphone unit to speak to anotheruser using a microphone in the GPS radio microphone unit, as well as totransmit location, waypoint, text messages, unit identification and auser identification name.

The unit uses the communication device's transmission method, regardlessif it is analog or digital, to transmit audio signals. For example, ifthe communication device is an analog two-way radio, the user pressesthe PTT button, communicates his message and after releasing the PTTbutton, but prior to the end of the transmission, the GPS radiomicrophone unit sends a fast frequency shift keying (FFSK) data burstover the audio carrier of the RF signal. The data burst is transmittedand received to all units on that radio channel within the operatingrange of the radio. The data burst includes multiple types ofinformation about that particular unit and user. For example, the user'sname, unit's hardware identification number, location, speed, direction,altitude and any text messages that the user may have composed. If thecommunication device is a digital radio, such as a cell phone, thenafter the user presses the PTT digital data is sent to each unit via thedigital modem. The data transmitted through the communication device ineither format may be in the form of a conventional NMEA sentence, in anyother standard format or in a proprietary NMEA sentence discussedherein. The GPS field units are programmed with a Group ID andIndividual ID Number. The ID numbers transmitted by one unit arereceived and stored on any GPS units that are programmed with the sameGroup ID as the sender. The sender may also send out information toselect receivers. This data is stored on the respective receiving uniton the unit's memory.

In addition to receiving a unit's information after the user has pressedthe PTT button, another user or person operating a base station or a GPSunit may “query” a particular unit. To query a specific unit the userselects the desired unit using the LCD display. Once selected the GPSunit sends a hex command, or other similar transmission, to the unitrequesting its information. The unit queried then transmits itsinformation back to the specific querying unit, all units or on a selectgroup of units. The querying unit and any other units receiving theinformation, then may display the queried unit's speed, direction,location, altitude, temperature and all areas that the user hastraveled.

The data transmitted in either analog or digital is able to be encryptedor remain non-encrypted. This option allows for some users, such as themilitary, to send sensitive information like troop location to otherusers. Additionally this option allows other users, such as search andrescue teams, the ability to transmit to all available receivers. Inaddition to transmitting the information to other users in the field,the GPS unit may transmit the same information to a base station orsimilar removed location by connecting the GPS unit to a computer orlaptop via the serial or USB connection. The base station may include acomputer and a monitor and display every user's location, altitude,temperature, speed, direction, etc., storing onto the PC as well as thereceiving GPS unit that is being used as an interface this information.In digital mode, the GPS device may or may not be used depending on theoperating requirements of the receiving station. For example, a digitalradio with a serial port may be directly connected to the serial port ofa personal computer. The digital radio may then receive all NMEAsentences and other radio transmissions sent by any GPS unit. Thecomputer may then extract the data from each of the NMEA sentences anddisplay the location, speed, direction, heading, altitude, waypoints,etc. of each unit.

The travel information is calculated by the microprocessor and the GPSreceiver. The GPS antenna receives positional signals from satellitesand the GPS receiver calculates the location of the device. Themicroprocessor uses those calculations to determine the course, averagespeed, maximum and minimum speed, estimated time of arrival at awaypoint, current speed and direction of the user. Additionally, theinformation allows the microprocessor to determine where the unit iswith respect to all the other units in the field.

In addition to transmitting his travel information, a user may connectthe GPS unit to a computer, flash drive, or personal digital assistantand download all the data stored in the GPS unit. This allows the userto track his progress and preserve a map of his travels. The data may beoverlaid on mapping software giving the user an exact map with notedlandmarks of his locations. Additionally, data from multiple units maybe downloaded to a single computer to create a detailed map of eachuser's progress and paths throughout a trip or excursion.

Referring now to the figures, FIG. 1 illustrates a front view of a GPSradio microphone unit 101 connected to a communication device 100. Thecommunication device 100 may be any type of device that includes anaudio input and output. For example, a digital or analog radio, cellphone, computer with radio or broadband access, mobile phone, personaldigital assistant, or a digital modem. The unit 101 transmitsinformation to other users through the communication device's 100communication method. This method may be analog or digital, for instancea broadband connection, cellular network, radio waves or hard-wiredcables. However, the GPS unit 101 may be integrated with a transceiverand receiver allowing the GPS unit 101 to operate as a standalone devicewithout the addition of a separate communication device.

In the embodiment illustrated in FIG. 1, the communication device 100 istwo-way radio and may include a speaker and microphone 104, displayscreen 107, PTT button 112, keyboard or number pad 108, connection jack109, volume and power controller 105, channel frequency controller 106,antenna 103 and battery (not shown). Additionally, the communicationdevice 100 may include a scrambler or serial port for encrypting digitaland analog signals. Depending on the type of communication device 100,more or less elements may be included. For example, if the device is acell phone or computer there may be no PTT button 112 or channelfrequency controller 106. Similarly, if the device is a two-way radiothere may be no display screen 107 or number pad 108. As there arethousands of communication devices on the market, the communicationdevice 100 shown in FIG. 1 is merely to illustrate how the GPS unit 101connects to a device and how the reception and transmission ofinformation operates.

In a two-way radio implementation the user manipulates the channelfrequency controller 106 to select a desired frequency at which totransmit signals. After selecting a matching frequency with otherradios, the radio can communicate with them. For example, when the userpresses the PTT button 112, the radio transmits audio picked up by themicrophone 104 and when the PTT is released the speaker omits audiotransmitted by other radios. Although FIG. 1 illustrates the volume andpower controller 105 as a singular knob those functions may be separatedinto multiple buttons or knobs. Similarly, the channel frequencycontroller 106 and PTT button 112 may be buttons, knobs or any othertypes of inputs.

Referring to FIG. 1 a, in a cell phone implementation, the communicationdevice is a conventional cell phone connected to the GPS unit. A cellphone 113 may include a number pad/keyboard 108, a connection jack 109,a display screen 107, a speaker/microphone 104 and an antenna. The GPSunit 101 is connected to the connection jack 109 of the cell phonethrough the signal cable 110, discussed in more detail below. Whenconnected, the GPS unit 101 transfers signals using the cellular networkautomatically through the signal cable 110. The user communicates over acellular network, using the number pad/keyboard 108 to select thecorrect connection number and then may hear and speak via aspeaker/microphone 104. An antenna 103 transmits the signals from thecommunication device 100 to other devices either through a radio networkor a cellular network, depending on the type of device selected by theuser.

For instance, in one embodiment, the GPS unit is connected to theconnection jack 109 which may be an existing microphone and speaker(e.g., headset input) connection of a conventional cell phone. The cellphone initiates a conventional call. To communicate with the GPS unitcoupled to the cell phone of a second subscriber, the first subscriber(after the cell connection is complete) presses the PTT button on theGPS unit and talks, and at the end when the PTT button is released, theaudio (microphone) output of the GPS device connected to the microphoneinput of the cellular device then transmits the audio FFSK burst fromthe GPS device, and the burst is transmitted to the second GPS unit inthe same manner as audio is transmitted over the cellular network. Thereceiving cell phone sends this audio data from the speaker outputconnection to the speaker input connection of the second GPS unit andthe second GPS unit then displays and stores the GPS location and/orother data sent by the originating GPS unit and cell phone.

Once the communication device 100 is connected to the GPS unit 101, theuser has the option of using only the input and output elements on theGPS unit 101 to communicate with others and the communication device 100acts to transmit and receive information, which is displayed andconverted to audio. Therefore, the communication device 100 may includeonly a receiver and a transceiver with audio signal capabilities.Additionally, as stated above, a radio receiver/transceiver may beintegrated within the GPS unit 101, allowing the GPS unit 101 to be astandalone device and operating without connecting to the communicationdevice 100.

The communication device 100 may have a connection jack 109 or an inputfor or an integrated wireless card. The connection jack 109 or wirelesscard connects the communication device 100 to the GPS unit 101. In oneembodiment the GPS unit 101 is connected to the communication device 100via a signal cable 110. The signal cable 110 connects to thecommunication device 100 through the connection jack 109 and connects tothe GPS unit 101 through the connection port 111. The signal cable maybe any type of cable and the connection end points may be configured toattached to a variety of communication devices. Additionally, theconnection port 111 may be a USB port or other type of cable connectionallowing the cable 110 to transfer signals between the communicationdevice 100 and the GPS unit 101. Similar to the connection jack 109, theconnection port 111 may include a integrated or attached network card towirelessly connect the GPS unit 101 to the communication device 100. Theconnection port 111 and the signal cable 110 may be designed in anymanner to transmit signals between the GPS unit 101 and communicationdevice 100, and any signal transmission method would suffice.

Once connected, either wirelessly or through a cable, the communicationdevice 100 and GPS unit 101 transfer a variety of signals between eachother. The connection allows the GPS unit 101 to operate and replace thecommunication device's 100 functions. For example, when connected, theuser of the GPS unit 101 may use the microphone input and speaker outputof the GPS unit 101, although the information is actually transmittedand received through the communication device 100. This provides theuser with flexibility, as he may wish to store the communication device100 and still be able to use its transmission functions. For example,the communication device 100 may be placed in a backpack or on a beltclip, far away from the user's mouth and the user may still communicateto others via the GPS unit's 101 speaker and microphone. Also, the GPSunit's 101 PTT button function allows for the user to press the PTTbutton on the GPS unit 101 to activate the PTT function on thecommunication device 100. However, the user may also use the inputs andoutputs on the communication device 100, even when connected to the GPSunit 101.

The signals transmitted between the GPS unit 101 and the communicationdevice 100 may include a PTT, positive and negative speaker andmicrophone inputs and outputs, data, ground, and power. However,depending on the type of communication device 100 and the type ofconnection to the GPS unit 101, these signals may vary. For example, theGPS unit 101 may receive a power charge from the communication device100 or may not receive any additional power from the device 100.Additionally, there may be more signals included, for instance if thecommunication device 100 includes a large display screen, the GPS unit101 may transmit signals allowing the icons on the GPS unit's 101 LCDscreen to be displayed on the communication device's 100 display screen.As state above, once the communication device 100 and GPS unit 101 areconnected, the user may use the GPS unit 101 to view and select allsignals that are transmitted to and from the communication device 100.For example, when the GPS unit 101 is connected to the cell phone 113the speaker input of the GPS unit 101 is connected to the speaker outputin the cable jack 109 of the cell phone, and the microphone input of thecell phone is connected to the microphone output of the GPS unit 101.This allows the GPS unit 101 to access and replace the functions of thecell phone 113.

FIG. 2 is a perspective view of the GPS unit 101. The GPS unit 101includes a GPS receiver 201, LCD screen 202, speaker 203, PTT button204, function key 205 power button 206, joystick 207, cancel button 208,SOS button 209209, microphone 210, internal circuitry (see FIG. 4) and acasing 211. The GPS unit 101 uses the communication device 100 totransmit and receive electrical signals, but once connected to thecommunication device 100 the user only needs to provide inputs to theGPS unit 101 to transmit and receive messages. For example, in oneembodiment, the functions of the communication device 100 may becontrolled by the GPS unit 101.

The GPS receiver 201 may include any type of antenna able to receivesignals from GPS satellites surrounding the Earth and any type of deviceable to perform GPS calculations. For example, the antenna may bepassive, active, re-radiating, or helix. Also, the receiver may be anelectronic chip, microprocessor or other electronic circuit able tocalculate location based on GPS satellite information. In oneembodiment, the GPS receiver 201 is positioned above the LCD screen 202,and the receiver and antenna are integrated into the GPS receiver 201.However, the receiver 201 may be placed anywhere on the GPS unit 101 ormay be detached from the unit 101. Additionally, the antenna may beexternal to the receiver 201. For example, the GPS unit 101 may includea cord or wireless connection allowing a detached antenna. An externalantenna could be placed on the roof of a car, clipped to a hat of auser, etc. for allowing better reception.

The receiver obtains the satellite data from the antenna and thencomputes the unit's latitude and longitude, speed, direction or travel,and when the GPS receiver 201 is able to receive positional signals frommore than two satellites the unit computes it's elevation The receivermay update the location of the GPS unit 101 every second or at any othertime interval. Also, in addition to the satellite information, the GPSreceiver 201 may also receive a Wide Area Averaging System (WAAS)signal. This signal allows for more precision in determining the unit's101 current position. However, in areas without a WAAS signal, thereceiver 201 may determine the unit's 101 location based on thesatellite signals. Furthermore, the receiver 201 and its functions maybe integrated within the internal circuitry of the GPS unit 101. Forexample, the GPS receiver 201 may only include a GPS antenna and theinternal circuitry of the GPS unit 101 may perform the positioncalculations.

The LCD screen 202 may be any type of electronic display such as liquidcrystal, plasma, light emitting diodes, vacuum florescent,surface-conduction electron-emitter display. Additionally, the LCDscreen 202 may be orientated anywhere on the GPS unit 101, for instanceit may be located on the back or front and may be any combination ofdimensions. In one embodiment, the LCD screen 202 is a liquid crystaldisplay which may include a layer to convert the linearly polarizedlight, normally emitted from a liquid crystal display, into circularlypolarized light. This layer allows a user with polarized sunglasses toview the screen without distortion. The LCD 202 is located on the frontof the GPS unit 101 towards the top, above the joystick 207, cancelbutton 208, SOS button 209, microphone 210, and speaker 203. The LCDscreen 202 may turn off or dim when not in use, helping to conserve thepower of the unit 101. Additionally, the LCD screen 202 includes abacklight that provides more contrast to the screen allow a user to viewit at night or in dim light conditions. The LCD screen is discussed inmore detail below, but generally allows the user to view informationabout his location or information about other users and additionallyallows the user to provide inputs such as audio, text messages andwaypoints, send other information to other users and navigate the menus.

The speaker 203 may be any type or size speaker and additionally may belocated anywhere on the GPS unit 101. In one embodiment, the speaker 203is located towards the bottom of the GPS unit 101 and below the LCDscreen 202. However, this location is not necessary for the operation ofthe speaker or GPS unit 101. The microphone 210 may be any device cableof detecting an audio noise and converting it to an electric signal.Similar to the speaker 203, the microphone 210 may be located anywhereon the unit 101. In one embodiment the microphone 210 is located betweenthe speaker 203 and the LCD screen 210. However, the microphone 210 andspeaker 203 are not essential for the GPS unit 101 to operate. The usermay use the microphone and speaker on the communication device 100 inorder to transmit audio communications to other users. Additionally, aheadset may be connected either wirelessly or through a cable to the GPSunit 101 allowing the user to have the speaker 203 and microphone 210elements closer to his mouth. Also, a two-way radio or a cell phone mayinclude microphone and speaker connections external to the device, suchas a car-phone, and as discussed above with respect to the headset, thespeaker 203 and microphone 210 of the GPS unit 101 may not be used bythe user to hear and transmit audio. Furthermore, the GPS unit 101 maybe used without audio communication capability between users. If the GPSunit 101 is used without audio capabilities, the user will be able totrack his own location, speed, altitude, temperature, direction andother travel information as well as that of the other users. However,the user will not be able to send audio communications to those users ifthe microphone portion has been disabled or not connected.

The PTT button 204 allows the unit to toggle between transmit andreceive modes for the GPS unit 101. Using a traditional analog two wayradio or broadband transceiver connected to the device, when the userpresses the PTT button 204, the device will activate a radio frequencycarrier of the two way radio and transmit the audio signals detected bythe microphone 210, such as the user's voice, and upon release of thePTT button, will turn off the microphone and allow an FFSK data burst tobe sent over the radio frequency carrier which will be transmitted overthe selected channel or frequency as set in the two way radio orbroadband device or (phone number in the case of a cellular phone). TheFFSK data burst includes the unit's information, such as identification,location, direction, speed, altitude, etc., which is received by unitsor computers that are on the same radio frequency or channel and thatmay or may not be part of the Group ID that the transmitting GPS devicehas been programmed for. The PTT button 204 may be any type of input,such as a knob, dial, switch or toggle. Additionally, the PTT button 204may be positioned anywhere on the GPS unit 101, however in oneembodiment the PTT button 204 is located on the side of the unit 101.

The function button 205 serves as an interface “quick jump button” forthe user to quickly select and jump between related user informationalscreens instead of exiting one function and entering another. When thefunction button 205 is selected, the unit displays a menu screen withthe names of certain functions. These names correspond to the samefunctions as the functional icons displayed on the main menu of the LCD202. When a name is selected, the unit displays the same information asif the user had selected a particular function via the functional iconon the LCD main menu.

The power button 206 allows a user to turn the GPS unit 101 on or off.The power button 206 may be a button, switch, knob or any type of input.In one embodiment the power button 206 is a depressible button and islocated on the side of the GPS unit 101. However, the power button 206may be any size or shape and be located anywhere on the unit, such as onthe top, back, bottom or front. Additionally, the power button may beconfigured such that it does not affect the use of the microphone andspeaker of the GPS unit 101. For example, the microphone and speaker ofthe unit may still be used by the user to communicate audio via thecommunication device 101, although the rest of the GPS unit 101, such asthe LCD and GPS receiver, is powered off. This allows the unit 101 to beused as a remote speaker/microphone for the communication device 100, inthe same way that a headset would be used.

The joystick 207 allows the user to select different functions on theLCD screen 202. The joystick 207 may be any type of input device, suchas a wheel, knob or touch pad. In one embodiment the joystick 207 is astick on a rotating pivot base. The joystick 207, moves a selection toolover different icons allowing a user to choose his preferred function.The joystick 207 may be located between the LCD screen 202 and thespeaker 203 or at any position on the unit, such as the back, side ortop. The joystick 207 is able to swivel 360° and may include an inputallowing the user to highlight and select a function by pressing down onthe joystick 207. Or the joystick 207 may include a depressible buttonon its top surface, allowing a user to press the top of the joystick 207in order to select an icon. Additionally, the joystick 207 may beomitted from the unit 101. For instance, the LCD screen 202 may be atouch-screen allowing the user to use his fingers or an object such as astylus to directly select an icon or function. Furthermore, the joystick207 may be combined with a touch-screen LCD 202 allowing the usermultiple options for selecting icons and other menu items.

The cancel button 208 is an escape button or back button and allows theuser to return to a prior menu or exit the current menu. The cancelbutton 208 may be a button, switch, knob or any type of input. In oneembodiment the cancel button 208 is a depressible button and is locatedon the front of the GPS unit 101 below the LCD display 202 and to theright of the joystick 207. However, the cancel button 208 may be anysize or shape and be located anywhere on the unit, such as on the top,back, bottom or front. The cancel button 208 activates two separatefunctions of the GPS unit 100. First, as discussed in greater detailbelow with respect to FIG. 4 and others, the GPS unit includes a mainmenu screen with functional icons displayed on the LCD. The main menuprovides access to numerous sub menus and device functionality. Thecancel button 208 is a menu navigation button that returns the GPS unitto the main menu from some sub menu or functionality. For example, whenthe cancel button 208 is selected the unit will display the previouslevel of the selected function that the user is currently navigating. Inone embodiment, the GPS unit is configured such that when a user pressesthe menu/SOS button momentarily, e.g., less than 2 seconds, while deviceis displaying a sub-menu or functional screen, the menu will exit thecurrent screen and return to the main menu. Second, the cancel button208 allows a user to go back one letter when using the virtual keyboarddisplayed on the LCD when using the text message function. Third, whenthe user selects and holds the cancel button 208 for two or moreseconds, the unit locks access to the various functions. This preventsthe unit from selecting any functions or alerting any settings if theuser accidentally brushes against the unit or touches the joystick.

The SOS button 209 configures the unit 101 to transmit a SOS alarm. TheSOS alarm transmits a distress message to all units within a user'sgroup or to all units and/or communication devices on the same frequencyat a certain time interval. The SOS signal may be used as an emergencylocation button to identify a user in need of assistance When a userpresses and holds the SOS button 209 e.g., greater than 2 seconds, theunit transmits a timed SOS message over the selected channel. The SOSmessage may be configured to provide the unit's position, direction,speed of travel, and altitude to other users. The SOS transmission maybe either transmitted via the third NMEA sentence discussed below, ormay be transmitted in any conventional NMEA sentence and only includethe unit's position information and identification. The SOS message maybe set to be transmitted at a specific time interval, for example everyfive minutes. This may be important if a user is injured or sick andknows he will not be able to repeatedly send out distress calls. Also,the automatic transmission of the SOS allows a user to focus on hiscurrent situation instead of remembering to transmit his location to allusers every few minutes.

Positional information may also be programmed for automatic periodictransmission, e.g., transmission every second or on some other periodicschedule, to allow tracking of the GPS unit (and hence the user). Forexample, a discrete GPS unit, numerous units, and/or a central controlcomputer coupled with a GPS unit may receive the periodic positionalbursts from a user with a GPS unit tracking a perimeter of a wild landfire, driving a truck, hiking, or in an airplane. Therefore, the centralcommand unit would receive positional data from the perimeter as it istransmitted from the device.

The cancel button 208 and SOS button 209 may be programmed usingfirmware to offer other quick and customized needs. For example, thecancel button 208 may be set such that when it is selected and held downfor four seconds it displays the Finder function or any function desiredto be quickly displayed by the user.

The casing 211 surrounds the internal circuitry and holds the elementstogether. The casing 211 may comprise any type of material, such asplastic, wood, metal, rubber or any combination of materials. In oneembodiment the casing 211 is a hard plastic that may be able towithstand significant forces. The casing may also be constructed of aflame retardant material offering a high temperature rating to withstanduse of the device within burning structures entered into byfirefighters. For instance, the casing 211 may be strong enough tosurvive a six-foot drop, if the user accidentally drops the GPS unit101. The casing 211 may also surround the buttons 204, 205, 206, 208,209, the joystick 207, speaker 203, microphone 210 in such a manner thatit blocks water, dust and other particles from reaching the internalcircuitry. In one embodiment the casing 211 seals around the perimeterof the LCD 202 to hold it in place. However, the casing 211 may be aclear color and completely cover the LCD 202, while still allowing theuser to view the display.

FIG. 3 is a diagram of the internal circuitry of the GPS unit 101illustrating the signals to and from the microprocessor 302. Theinternal circuitry 300 comprises any type of circuit board or multiplecircuit boards connected to each other, such as a printed circuit boardor hybrid integrated circuit. The internal circuitry 300 comprises theelectrical connections and components for the GPS receiver 201, LCDdisplay 202, joystick 207, speaker 203, microphone 210, PTT button 204,compass 401, output driver 403, microprocessor 302, memory and datastorage 304, clock 305, encoder/decoder 306, USB to UART 407, powersupply charger 308 and battery 309. Additionally, the internal circuitry300 provides outputs to the connection port 111 allowing the GPS unit101 to control the functions of the communication device 100 and receiveand transmit information through the communication device 100. Also, thecircuitry 300 provides an input for a cable to recharge the battery 309.

The microprocessor 302 receives electronic signals and executes programcode to achieve the correct outputs. Any type of microprocessor may beimplemented within the circuitry 300 depending on the desired speed andfunctionality of the GPS unit 101. Additionally, the microprocessor 302may be a single chip or multiple processors linked together. Themicroprocessor 302 receives inputs from the GPS receiver 201 and maycalculate and store the location of the unit 101. The microprocessor 302performs calculations related to the different functions of the GPS unit101. For example, the microprocessor 302 uses the location informationand time to determine distance traveled, speed, course, estimated timeof travel to a waypoint or point of interest, and the directionalrelationship and distance to other units. The microprocessor 303 drivesthe LCD 202 to display different menus, screens and informationdepending on the inputs from the joystick 207. The microprocessoroperates the LCD 202 through the use of an output driver 303, whichdrives the functionality and display based on signals received from themicroprocessor 302. The microprocessor 302 also receives inputs from aclock 304, encoder/decoder 306, speaker 203, PTT button 204, memory 304,microphone 210 and compass 301. Furthermore, the microprocessor 302 mayincluding mapping software allowing a user to see his exact locationdisplayed on the LCD on any type of map, including topographic, street,or contour.

The microprocessor 302 formats the information to be transmitted in NMEAsentences. In addition to conventional NMEA sentences, themicroprocessor 302 may use three additional NMEA sentences. Thesesentences, detailed below, allow a user to text message other users,send waypoints directly to each user, locate other users and view theircurrent location, altitude, course and speed. Each sentence may bedesigned to include any information, for instance the groupidentification may or may not be included and the different transmittedpieces of information may be included in any of the sentences or in anyorder. Additionally, the NMEA sentences are not limited to only the GPSunit 101 but may be used within any transmission device using a NMEAstandard or format.

The three sentences each begin with a “$” character and include anasterisk “*” before the checksum and sentence delimiter. The $ characteralerts the receiver to the beginning of the NMEA sentence. The checksumconsists of two hex digits that follow the asterisk. The hex digits arethe sum of the bits between the $ and *, or any number of bitscombination. The receiver adds the bits it has received and thenverifies the accuracy of the sentence transmitted by comparing its sumwith the checksum number. If the checksum number and the receiver'snumber do not match, the receiver may discard the sentence because itmost likely contains errors. After the checksum, each sentence includesa carriage return linefeed indicating the end of the sentence. Forexample, each sentence ends with 0D 0A which alerts the receiver thatthe sentence has terminated.

The first NMEA sentence has the following formula:$GPWPL,DD.MMMMM,d,DDD.MMMMM,d,<WaypointName>,<ICON>,<Altitude>,<SCODE>,<GroupID>,<Date>,<Time>*CC<CR><LF>. The first NMEA sentence includes aseries of data fields pertaining to the type of transmission, locationof the user, waypoint name, waypoint ICON index, altitude, transmittedSCODE, group identification name, data, time, checksum and sentencetermination delimiter, each of which are discussed in turn. First, thebeginning of the first NMEA sentence, as well as the second and thirdsentences, starts with a $. As discussed above, this indicates thebeginning of the sentences. A transmission type of the sentence isrepresented by “GPWPL” which indicates that the sentence is a designatedwaypoint intended for a GPS receiver. For example, the “GP” indicates tothe receiver that it is designated for a GPS receiver and the “WPL”indicates that the following data is a waypoint location.

A waypoint is a set of coordinates that define a specific location.Waypoints may be used to indicate a meeting point for different users orto let a user send a location where he has previously been or intends tohead towards. The waypoint positional information includes latitude andlongitude, given in terms of degrees, minutes and direction. The degreenumber for latitude ranges between 0 and 90 and the degree number forlongitude ranges between 0 and 180. The minutes number range for both isbetween 0 and 99,999. The direction symbols for latitude are N forNorth, S for South and for longitude are E for East and W for West. Thesentence format for latitude and longitude is DD.MMMMM,d. With the firstsequence DD.MMMMM,d being degrees “DD”, minutes “MMMMM”, and direction“d” of latitude. The second sequence DDD.MMMMM,d being degrees “DDD”,minutes “MMMMM”, and direction of longitude “d”. The microprocessordetermines the degrees, minutes and direction for both latitude andlongitude based on the coordinates entered directly by the user or by alocation selected by the user using the LCD display.

The waypoint name format may be up to 10 ascii text characters, such as“redcanyon” or any name desired by the user. For example, the user maychoose a name based on the name of land feature or location, i.e. “redcanyon” or a name that indicates which users should meet at thewaypoint, i.e. “group1” or a name that indicates the time when he passedthrough the coordinates, i.e. “9 am”.

After the waypoint name is the ICON data field. The ICON data fieldincludes the waypoint ICON index and may be displayed as a hex value.The ICON data field contains a reference to the waypoint ICON. Forexample, when the user marks a waypoint, in addition to selecting a nameor number for the waypoint, the unit also allows a user to select acertain icon or graphic. For instance, with a search and rescue mission,a user may mark a certain waypoint with a “body” icon illustrating thathe has found a person's body at that location. The ICON data fieldtransmits the selected graphic reference number to the receiver suchthat the may then display the correct graphic along with the waypointname. The ICON index is a reference to the graphic and the graphic manynot actually be transmitted, only its reference number.

Following the ICON sentence data, is an altitude data field. Thealtitude is a numerical measurement reading of the altitude of the GPSunit. The altitude measurement is the altitude of the waypoint locationbeing transmitted. In one embodiment, the altitude value may rangebetween −250 and +1250 meters. However, the numerical reading may befeet, yards, miles or any other length or height unit. The largenumerical range available allows a unit to display an altitude, even ifthe location is underground, such as a cave or below sea level. Thealtitude of the waypoint is determined by the microprocessor based on ananalysis of the satellite positional signals received by the GPSreceiver.

A SCODE data field is included after the altitude data field. The SCODEis a unique identifier represented in hex. This identifier is unique forevery GPS unit and enables a user to query or transmit information to aspecific unit, without sending the data to all groups. The SCODE datafield is populated with a serial code 24 bit hex value with a range of000001 to FFFFFF hex. This number indicated to the receiver the unitwhich send the sentence and additionally where to send replyinformation.

A group identification data field allows the unit transmitting awaypoint to indicate which users the waypoint is meant for. The groupidentification number may range between 01 to 99. Additionally, the datafield may be populated by text characters or by a combination of textand numerical characters. For example, if the group name is “A2” thegroup identification number included in the NMEA sentence would be “A2”.For example in a search and rescue operation there may be one group(group 01) consisting of several members looking for the missing personand another group (group 02) consisting of several medical personnel toassist either the search members or the missing person when he islocated. The group identification allows for all users to know whichwaypoints are directed to them and which waypoints are directed to otherusers. In the search and rescue mission the medical personnel maytransmit the location of the nearest hospital and the search memberswill be know that the waypoint indicating the hospital is directed onlyto the medical personnel and not the search members. However, there maybe instances where all users need to know a certain location. In thiscase the group identification transmitted will be 00. For example, ifthe search and rescue members find the missing person the location willbe transmitted too all members with the information that it is directedtowards every group member.

Following the group identification data field, are the date and timefields. The data and time data fields are numerical values that indicatethe time and date that the waypoint was selected and transmitted by theuser. The date format is “yymmdd”, with yy indicating the year, mmindicating the month and dd indicating the day. The year number “yy” mayrange between 00 and 99, for example for the year 2009 the value wouldbe “09”. The month number is between 01 and 12, with January representedby 01. For example, if the month is May the month will be “05”. The day“dd” ranges from 01 to 31 and represents the day in the month. Forexample, the 14^(th) of May would be “14”. The full date format for May14, 2009 would be, “090514”. The time format is “HHMMSS”, with HHindicating the hour, MM indicating the minutes and SS indicating theseconds. The hour number HH ranges between 00 and 24, for example 7:00a.m. would be “07” and 3:00 p.m. would be “15”. The minutes number MMranges between 00 and 59, for example 15 minutes after the hour would be“15”. The second number SS ranges between 00 and 59, for example, 30seconds after the minute would be “30”.

Finally, the first sentence ends with an asterisk “*” followed by thechecksum digit and the carriage return, line feed. As discussed above,this indicates the end of the sentence and allows the receiver to verifythe accuracy of the information received in the first sentence.

A specific example of the first NMEA sentence transmitting a waypointlocation named “redcanyon” at 6:43 a.m. on Jan. 28, 2008 with a groupidentification of 01 would be: $GPWPL,25.12345, N,121.12345,E,redcanyon, 06,100,000001,01,080128, 064300*CC<CR><LF>. After thedollar sign and transmission type the first three data fields representsthe latitude information. The 25 is the degrees, 12345 is the minutesand the direction is North, so the latitude is 25.12345 degrees North.The next three data fields represent the longitude information. The 121is the degrees, 12345 is the minutes and E is direction East, so thelongitude information is 121.12345 degrees East. The next data field isthe waypoint name, red canyon. This is followed by the ICON indexnumber, 06 representing the reference graphic number 6 of the graphicillustrations available to illustrate a waypoint on each unit. The nextdata field is the altitude and indicates that the unit is at a height of100 meters. This is followed by the SCODE 000001 which indicates theunit identification of the user sending the waypoint, the unit hardwareis 000001 indicating unit 1. The group identification number is 01 andthe date is Jan. 28, 2008 represented by 080128 and the time thesentence was transmitted was 6:43 a.m., represented by 064300.

The first NMEA sentence may be used to transmit waypoints to differentusers allowing for easy and more efficient communication of locationdata. For example, if a search and rescue team is attempting to locate amissing team member, each member of the search and rescue team cantransmit the locations that they have searched. Also, members cantransmit to other members the locations of places of interest, such asthe place where the missing person's backpack, cup or other personalbelonging was found. For example, in the specific sentence discussedabove, a user sent a waypoint called red canyon to all other members.The sentence transmitted the exact coordinates of the location and thetime that the waypoint was set. This allows members to know the exactlocation and name of the area or place the user or team member wanted toillustrate. Additionally, because the date and time are transmittedalong with the waypoint information, other members and users will knowif this is a new waypoint or what time a member passed through thislocation. This function helps the search and rescue members to moreefficiently canvas an area and be able to narrow the search accuratelyby marking specific locations and more quickly locate the missingperson.

The format for the second sentence may be, $GPWMS,<Message>,<NameId>,<SCODE>,<GroupID>,<Status>, <ICON>*<CKSUM><CR><LF>. The second NMEAsentence includes a series of data fields pertaining to the type oftransmission, text message, name identification of the user, transmittedSCODE, group identification, status, ICON, checksum and sentencetermination delimiter, each of which are discussed in turn. First, thebeginning of the second NMEA sentence, starts with a $. As discussedabove, this alerts the receiver to the beginning of the sentence. Atransmission type of the sentence is represented by “GPWMS” whichindicates that the sentence is a text message intended for a GPSreceiver. For example, the “GP” indicates to the receiver that thesentence that it is designated for a GPS receiver, the “WMS” indicatesthat the following data is a text message.

The text message data field follows the transmission type data field.The text message field allows for 39 characters of ascii text. Thesecharacters are selected by the user using the LCD screen and joystick.The text message allows for users to communicate to each other withouthaving to speak. The actual message may be any combination of charactersthe user chooses. The name identification follows the text message datafield. The name identification provides the user's name who is sendingthe text message. The name of the user may be selected by the usercomposing the text message or may be populated automatically by themicroprocessor, using the memory settings including the unitidentification. The name of the user includes up to 10 text charactersof ascii code.

The SCODE and group identification data fields follow the nameidentification data field. The SCODE and group identification fields arethe same format and include the same types of information as the firstNMEA sentence. See above for a more complete description of theirformats.

A status data field follows the group identification. The status fieldincludes a hex numeral and ranges between 00 and FF hex. Bit 0represents that the status GPS is valid. If the status of the GPS isvalid then the receiver will know that the location data and waypointinformation is accurate. However, if the status display illustrates thatthe GPS is not accurate the receiving user will understand the positioninformation is approximate. For example, in an open area, typically theGPS receiver will be able to receive positional signals from threesatellites, which insures that the position information is accurate.However, in certain conditions, such as in a forest or cave, the GPSreceiver many not be able to receive as many positional signals. Thedata for the waypoint and other position information must then becalculated by the microprocessor. The status data field allows thereceiver user to know if the waypoint location is accurate or anestimate performed by the GPS microprocessor.

A ICON data field is after the status, the ICON number ranges between 00and 99. The ICON number is a reference to a particular graphicillustration stored in the memory of each GPS unit. The icons stored maybe changed, added or removed as desired by different users. The ICONSdata field includes the reference number of the icon graphic includedwith the text message sent by the transmitter. Similar to the waypointICON index, the ICON number data field allows the receiving unit tocorrectly display the correct icon selected by the transmitting user.

Finally, the first sentence ends with an asterisk “*” followed by thechecksum digit and the carriage return, line feed. As discussed above,this indicates the end of the sentence and allow the receiver to verifythe accuracy of the information received in the second sentence.

A specific example of the second sentence, in which a text message sentfrom peter586 saying “Hello World” transmitted would be: $GPWMS,HelloWorld,peter586,000010,02,01,00*<CKSUM><CR><LF>. After the dollar signand transmission type, the next data field is the text message. Thismessage included “Hello World”. The data field following the textmessage is the user name, peter586. The next data field is the SCODE000010, which indicates that the unit sending the information is unitnumber 10. The group identification is next and indicates that the groupid is 02. The status data field is 01 indicating that the status for theGPS fix is valid. Finally, the ICON data field is 00 indicating thatreference graphic 00 has been selected by the transmitting user. Thesecond NMEA sentence allows for users to communicate without speech andwithout making too much noise. For example, if a military soldier is inenemy territory he can transmit messages, such as “need medicalattention” or “enemy planning an attack for 1 am” to other users orsoldiers without being heard or detected by the enemy. Additionally thesecond sentence allows for users to transmit messages to all other userssimultaneously. This may be more effective then attempting tocommunicate using audio to each member. For example, search and rescueteams can transmit information to all members simultaneously through asingle message saving the time it would take to alert each individualseparately.

The format for the third sentence maybe:$GPWGT,<FixStatus>,DD.MMMMM,d,DDD.MMMMM,d,<Altitude>,<COURSES>,<SPEED>,<NameId>,<SCODE>,<GroupId>,<Status>,<ICON>,<Date>,<Time>*CC<CR><LF>.The third NMEA sentence includes a series of data fields pertaining tothe type of transmission, GPS fix, location information, altitude,course, speed, name identification, SCODE, group identification, status,date, time, checksum and sentence termination delimiter, each of whichare discussed in turn. First, the beginning of the third NMEA sentence,similar to the first and second sentences starts with a $. As discussedabove, this alerts the receiver to the beginning of the third sentence.A transmission type of the sentence is represented by “GPWGT” whichindicates that the sentence is user travel information intended for aGPS receiver. For example, the “GP” indicates to the receiver that thesentence that it is designated for a GPS receiver, and the “WGT”indicates that the following data is information related to travel,speed and distance of a unit.

A fix status data field indicates whether there is a valid GPS statusfix, i.e. whether the GPS receiver has been able to locate the currentGPS position accurately. For example, if the GPS receiver is able toreceive position signals from more than one satellite it can determinethe position accurately, but if cannot receive signals from more thanone satellite it will not be able to accurately determine the position.The fix status is a text character and may be “A” representing a validGPS fix or “V” representing an invalid GPS and no fix. This allows theunit to know whether the location data included within the NMEA sentenceis accurate, or whether the location information may be inaccurate.

A location information data field includes a set of coordinates thatdefines the specific location of the unit at the time the NMEA sentencewas transmitted. The location information includes latitude andlongitude, given in terms of degrees, minutes and direction. The degreenumber for latitude ranges between 0 and 90 and the degree number forlongitude ranges between 0 and 180. The minutes number range for both isbetween 0 and 99,999. The direction symbols for latitude are N forNorth, S for South and for longitude are E for East and W for West. Thesentence format for latitude and longitude is DD.MMMMM,d. With the firstsequence DD.MMMMM,d being degrees “DD”, minutes “MMMMM”, and direction“d” of latitude. The second sequence DDD.MMMMM,d being degrees “DDD”,minutes “MMMMM”, and direction of longitude “d”. The microprocessordetermines the degrees, minutes and direction for both latitude andlongitude based on the current location of the unit calculated by theGPS receiver.

Following the location data, is an altitude data field. The altitude isa data format providing a numerical reading of the altitude of the GPSunit, determining the current height of the unit. In one embodiment, thealtitude value may range between −250 and +1250 meters. However, thenumerical reading may be feet, yards, miles or any other length orheight unit. The large range available allows a unit to display analtitude even if the location is underground, such as a cave or belowsea level.

A courses data field follows the altitude data field. The courses numberranges between 000 and 359 and represents the degrees of the currentheading of the unit. For example, if a user is heading 90 degreestowards the Northeast, the course number stored and transmitted will be90 degrees. This course information allows the user receiving the NMEAsentence to better predict future locations of the user sending theinformation. For example, using the course information received alongwith the last position, a user may point to the current location on amap and then use the travel course to extrapolate the next location ofthe transmitting unit.

A speed data field is located after the course data field. The speedindicates the current speed of the unit when the NMEA sentence wastransmitted. The format for the speed ranges between 0 and 999kilometers per hour. However, the speed may be formatted to be miles perhour or any other speed unit measurement. The speed data allows a userto know how fast another user is traveling. Also, the measurement allowsthe unit to better predict when another unit will reach a certaindestination. For example, similar to the manner in which a user maydetermine a future location of a particular user using the courseinformation, the microprocessor can determine when a certain unit willreach a destination. Based on the current location, course and speed aswell as distance to a particular location the microprocessor cancalculate the estimated time of arrival of the transmitting unit to thatlocation.

A name identification data field follows the speed data field. The nameidentification provides the name of the user whose information is beingtransmitted. The name of the user may be selected by the user sendingthe information, or may be populated automatically by themicroprocessor, using the memory settings including the unitidentification. The name of the user includes up to 10 text charactersof ascii code.

A SCODE data field is included after the name identification data field.The SCODE is the unit identification number of the GPS unit transmittingits information. The SCODE is the same format and include the same typesof information as the first NMEA sentence. See above for a more completedescription of its format.

A group identification data field is included and allows the unittransmitting the travel information to indicate to which group the usersending the information belongs. The group identification number mayrange between 01 to 99. Additionally, the data field may be populated bytext characters or by a combination of text and numerical characters.For example, if the group name is “A2” the group identification numberincluded in the NMEA sentence would be “A2”. The group identificationnumber is the same format and includes the same information as the firstNMEA sentence. See above for a more complete description of its format.

A status data field follows the group identification. The status fieldincludes a hex numeral and ranges between 00 and FF hex. Bit 0represents that the status GPS is valid. The status data field is thesame format and information as the first NMEA sentence. See above for amore complete description of its format.

A ICON data field is after the status, the ICON number ranges between 00and 99. The ICON data field is the same information and format as thesecond NMEA sentence. See above for a more complete description of itsformat.

Following the ICON data field, are the date and time fields. The dateand time data fields are numerical values that indicate the time anddate that the travel information was transmitted by the user. The dateformat is “yymmdd”, with yy indicating the year, mm indicating the monthand dd indicating the day. The year number “yy” may range between 00 and99, for example for the year 2009 the value would be “09”. The monthnumber ranges between 01 and 12, with January represented by 01. Forexample, if the month is May the month number will be “05”. The day “dd”ranges from 01 to 31 and represents the day in the month. For example,the 14^(th) of May would be “14”. The full date format for May 14, 2009would be, “090514”. The time format is “HHMMSS”, with HH indicating thehour, MM indicating the minutes and SS indicating the seconds. The timeformat is the time that the travel information was collected andtransmitted. The hour number HH ranges between 00 and 24, for example7:00 a.m. would be “07” and 3:00 p.m. would be “15”. The minutes numberMM ranges between 00 and 59, for example 15 minutes after the hour wouldbe “15”. The second number SS ranges between 00 and 59, for example, 30seconds after the minute would be “30”.

Finally, the third sentence ends with an asterisk “*” followed by thechecksum digit and the carriage return, line feed. As discussed above,this indicates the end of the sentence and allow the receiver to verifythe accuracy of the information received in the third sentence.

A specific example of the third sentence, sent from Joe at 6:36 a.m. onJan. 28, 2008 with a speed of 25 km/hr and a course of 359° would be:$GPWGT, A, 25.12345, N,121.12345, E,100,359,25, Joe,000001,01,01,01,080128,063600*CC<CR><LF>. After the dollar sign andtransmission type the first data field represents the fix status and Ais displayed representing that there is a valid GPS satellite fix. Afterthe fix status, the next three data fields represents the latitudeinformation. The 25 is the degrees, 12345 is the minutes and thedirection is North, so the latitude is 25.12345 degrees North. The nextthree data fields represent the longitude information. The 121 is thedegrees, 12345 is the minutes and E is direction East, so the longitudeinformation is 121.12345 degrees East. The next data field is thealtitude and indicates that the unit is at a height of 100 meters. Thedata fields following altitude are the course information, speed andname identification, 359 indicating that the unit is on a course of 359degrees and 25 indicating that the user is traveling at 25 km/hr and theuser is Joe. These data fields are followed by the SCODE 000001 and ICON01 indicating that unit 1 is sending the positional information and thatthe user has included graphic reference number 1 along with hislocation. The group identification number is after the ICON field and is01. Also the status is 01, indicating that the GPS has a valid statusfix. The next fields are the date and time, 080128 indicating that thesentence was sent on Jan. 28, 2008 and 063600 at 6:36 a.m. The thirdsentence allows the unit to compute for different users their estimatedtime of arrival to a particular location, future destinations as well asdisplay each user's current path, speed, heading and current location.For example, in a search and rescue operation, members of the team willbe able to determine how quickly other members can reach them if theyfind the missing person or if they themselves become endangered.Additionally, the third sentence allows for the team to estimate howquickly they will be able to canvas an entire area and track eachmember's progress and travel information.

The microprocessor 302 outputs a variety of signals to the radiointerface 111. In one embodiment, all data other than voicecommunications, is transmitted from the GPS unit 101 in the form of NMEAsentences. If the communication device is analog, the data is sent atthe end of the voice communication when the PTT button is released.After the PTT is released, the unit automatically generates andtransmits a fast frequency shift keying (FFSK) audible burst. The FFSKencodes the NMEA sentences into a format that is easily transmitted overradio waves. For example, the NMEA sentence is encoded to a series ofbits which is then transformed into high and low frequency radio waves.The receiver at the end then decodes the varying frequency waves into aseries of bits which is then transformed into the original NMEAsentence. The communication device is digital, the modem sends data overthe data channel of the radio after the PTT has been released.

Similar to the two-way radio function, a cell phone may also transmitthe FFSK audible burst including the NMEA sentences. The user uses hiscell phone to dial another phone and after connected presses the PTTbutton on the unit. When the button is released the FFSK audible burstis transmitted through the cell phone to the cellular network. The FFSKis then decoded, either by a GPS unit coupled with a receiving cellphone or directly by the other cell phone should the cell phone beconfigured in accordance with aspects of this disclosure, when it isreceived. A user may also use a cell phone with a digital modemconnecting the device to the data port of the digital cell phone and usethe digital data modem portion to send and receive information betweentwo units. Additionally, the user may be able to communicate and senddata between more units if a telephone conference option or 3-waycalling is provided by the cellular network provider.

The microprocessor 302 may produce a number of output signals, includingan FFSK encoded audio signal, which may include one or more of theabove-referenced NMEA sentences, voice, a PTT output that triggers theassociated PTT functionality on the attached two way radio. Themicroprocessor may further include a serial data port interface 307 anda USB port interface 307. The input and output configurations providethe GPS unit a variety of different methods for data transmission. Forexample, the FFSK is used for radio wave transmission, the serial dataport and USB port allow for digital transmission. The type of signalsactually used by the communication device 100 depend on the type ofdevice. If the communication device is an analog radio or datatransmission over audio (such as a cell phone) then the output datasignal will be an FFSK burst after the voice transmission. If thecommunication device is a digital radio then output data is sent throughthe digital modem of the device. For example, if the communicationdevice 100 has a digital transmission mode then the FFSK audio signalwould be ignored.

The microprocessor 302 of the GPS unit 101 receives a number of inputsignals from the communication device 100. The microprocessor 302processes the input signals and provides the signals to one of severalpossible connected functional processing elements. For example, when thedevice receives a FFSK signal and an audio signal from the communicationdevice 100, the signal is processed encoder/decoder 406, which decodesit and sends it to the microprocessor 302. The microprocessor also sendsthe audio signal to the speaker 203 and stores any other data includedwithin the signal in the memory 304 and/or displays it on the LCD 202.Similarly, the microprocessor may receive voice data from the microphoneinput 210, which voice data is subsequently processed by the encoder 306and transmitted to another device by way of a two way radio coupled withthe GPS unit, for example. However, the signal inputs and outputs of themicroprocessor 302 may include more or fewer signals than discussed. Thesignals depend on the functions of the GPS unit 101, for instance, thecompass 301 may be omitted from the unit 101 and therefore themicroprocessor would not receive a compass input. Additionally, morefunctions may be added, such as camera and then the microprocessor wouldthen also include a signal to and from the camera.

The microprocessor 302 stores information it receives in the memory 304and performs calculations and executes various other actions based, atleast in part, on the stored information. For example, themicroprocessor 302 receives data from the GPS receiver 201 and compass301. The data is processed and the received information is stored in thememory 304. Hence, the processor may store in memory latitude andlongitude information, a time and date stamp, along with headinginformation from the compass. Calculations may then be performed by themicroprocessor 302 with the data inputs being time, date, latitude,longitude, user speed and direction and altitude.

Additionally, when the communication device 100 receives a radiotransmission, the encoder 306 provides the data to the microprocessor302. The microprocessor 302 then stores the data, such as text messages,along with the group and unit identification numbers of thetransmission, the location, speed, direction of travel, and altitude ofthe transmitting device as well as showing on the receiving party's LCDscreen that a transmission has been received by an individual as well astheir location. Various methods performed by the microprocessor 302using information stored within in the memory 304 may provideinformation sufficient to display on the LCD 202 position, bearing,speed, etc., information for the device as well as position, bearing,speed, etc., information received from other devices. The data in memorymay also be used by the processor to plot a course to a target location(entered by the user, or determined from other user data), estimate timeof travel to the target location or another location and send messagesto other users.

The compass 301 is a computing module, implemented in hardware,software, and/or firmware, that provides the directional bearing of theGPS unit 101. It should be noted, that various modules illustrated inFIG. 3 may be implemented in hardware, software, and/or firmware. Thecompass module is coupled with the microprocessor. The compass modulemay also be connected with the GPS receiver directly, or be configuredto obtain positional information from the microprocessor 301. Themicroprocessor receives the directional bearing information from thecompass and displays the bearing information on the LCD screen 202 whenthe user selects the compass function, such user selection beingdiscussed in further detail below. The compass 301 in one embodiment isan electronic compass with magnetic sensors that provide geomagneticdata to the microprocessor 302 in order to determine the unit's bearing.In one embodiment, the compass is the TOSHIBA YAS525B electroniccompass. However, the compass 301 may be any device capable ofdetermining the directional heading of a device and is not constrictedto only electronic devices. For example, the compass 301 may comprise amanual magnetized needle compass with a display next to the LCD screen202.

The memory 304 stores and provides access to all types of data for theGPS unit 101. The memory may be any type of memory such as volatile ornonvolatile memory and may have any size storage. In one embodiment, thememory 304 is nonvolatile solid state memory. The memory 304communicates with the microprocessor 402 to receive data and providesdata to the microprocessor to be transmitted or displayed. The memory304 stores the user's identification name, group name as well as ahardware identification. The user identification and group name may bechanged by the user, however the hardware identification is specific tothat GPS unit and acts as a serial number for the unit and may be set tonot be able to be modified by the user. Some or all of the data storedin the memory 304 may be able to be downloaded to a computing device,such as a personal computer, personal digital assistant, another radio,a removable memory device (e.g., a jump drive coupled with the USBport), etc. or other external storage. The user may choose to downloadthe entire memory or only selections of the memory. Memory capacity maybe managed on a first in first out basis, as well as in other ways.

The battery 309 provides power to the internal circuitry 300 and the GPSunit 101. The GPS unit 101 may operate without the battery, for exampleit may include a power cord or other type of power source. Additionallythe battery 309 may be rechargeable or replaceable and may be any typeof battery such as nickel-cadmium, nickel-metal hydride, lithium ion,polymer, alkaline or lead-acid. The battery may connect internallyinside the casing 211 of the GPS unit 101 or may connect to the outsideof the GPS unit 101. For example, a battery clamshell may be usedallowing the GPS unit 101 to run on an internal battery 309 as well asdisposable external batteries. In addition to the battery 309, theinternal circuitry 400 includes a power supply charger 308. The powersupply charger 308 may recharge the battery or provide power itself tothe GPS unit 101. The power supply charger 308 may provide power to thebattery 309 or the unit 101 from any source. For instance, the charger308 may be connected to a power outlet, an external battery, computer orto the power source of the communication device 100. The power charger308 may be connected to the power source through any type of cable, suchas a USB cable or charging cable. In one embodiment, the power charger308 connects to a power source through a USB five volt connection cable.In another embodiment, the GPS unit 101 may be connected to thecommunication device's auxiliary power connection. This allows thebattery 309 to be recharged and additionally provides power to the GPSunit 101. This helps to give the GPS unit 101 additionally battery lifeand thus more time in the field.

The encoder/decoder 306 encodes and decodes radio analog signals sentand received by the GPS unit 101. The encoder/decoder may be any deviceor electronic circuit able to change an electronic signal into a codeand when receiving a coded signal can return it to its original form. Inone embodiment, the encoder/decoder 406 is a fast frequency shift keying(FFSK) encoder/decoder, which encodes binary 0s and 1s into differentfrequency cycles. For instance, if the data format is FFSK the encodertranslates the signal into the correct format and then sends the newlyformatted signal to the microprocessor 302 to be sent to thecommunication device 100 via the connection port 111.

In another embodiment, when the data format is a digital signal, theencoder and decoder encodes the electronics signal into a format able tobe transmitted by the transmitting modem. For example, the encodertranslates the information into a series of audio signals which are thenable to be transmitted by the modem. When the unit receives a codedsignal the encoder/decoder decodes the data by translating it from aseries of audio signals back into 0s and 1s. After the data signal isencoded for transmission it may be encrypted. If it is a digital signalit may be encrypted through the data port, and if it is FFSK format itmay be encrypted by a scrambler. In both cases, the encryption devicemay or may not be an internal component of the two way transceiver andmay be external. The data port and scrambler may be located in the GPSunit 101 or within the communication device 100, and may be any devicecapable of encrypting a signal. For example, an encryption circuit maybe implemented within the internal circuitry 300 of the GPS unit 101 ormay be integrated within the communication device 100. Encrypting thesignal before transmission allows for sensitive data to be transmittedbetween GPS units 101.

The USB UART 307 provides connectivity options for different dataformats. In one embodiment, the USB UART signal 207 allows data signalsto be sent both through a USB output and a serial data output. Thisallows the GPS unit 101 to connect to any type of communication device.Also, the signal may be modified to be able to connect to any other dataformat, further increasing the flexibility of the GPS unit 101.

FIG. 4 illustrates the main menu screen illustrated on the LCD 202display. The icons and functionality accessed by way of the icons areillustrative of some of the device functionality that is provided byvarious aspects of the present disclosure. The display options and iconsare driven by the microprocessor 302 as discussed above. The main screendisplays a number of informational and functional icons. First beginningwith the informational icons, in one embodiment, each informational iconis representative of some operational aspect of the unit 100. Further,the informational icons display data continuously and the user does notneed to go through a menu hierarchy in order to receive information. Theinformational icons may include a battery power indicator 417, powersource indicator 418, keypad lock 419, GPS status 420, data TX/RX 421,time 422, log enable 410, G-mouse/NMEA data out 412, backlight status413, group people 415, message 416, date 411 and temperature 414. Theinformational icons may alter in appearance or may not be present,depending on the status of the information that they are designed toindicate. For example, if the user has not received any messages, themessage icon 416 is not displayed on the LCD screen 202. Additionally,the informational icons may be designed as any suitable display graphic,may be located anywhere on the LCD screen 202 or may be partially orcompletely omitted. Furthermore, the user may select which icons hewishes to have displayed on the screen 202 by selecting the tools icon.

A battery power indicator 417 illustrates the power level of thebattery. In one embodiment the power is indicated by a graphic of abattery that progressively becomes “empty” as the power level decreases.For example, when the battery is fully charged the graphic display isfilled in entirely, when the power level has been decreased by 20% thebattery graphic is filled only to 80%. However, the battery powerindicator 417 may be designed to have any appearance, for instance itmay simply display the numerical percentage of power, may include barsthat decrease or any other graphic able to inform the user of the amountof power remaining in the battery.

A power source indicator 418 illustrates the power source providingpower to the GPS unit 101. The GPS unit 101 may provide its own powerthrough the battery, or may receive power from an external connection.For example, the communication device 100 or an external battery mayprovide power to the unit 101. In one embodiment, the power sourceindicator 418 is a graphic design of a power-plug, however it may bedesigned in any suitable graphic. The power source indicator 418 isilluminated if the GPS unit 101 is receiving power from thecommunication device 100, or another source of external power such as anelectrical cord.

A GPS status icon 420 illustrates to the user the satellite fix of theGPS receiver 201. In one embodiment, there are four graphics, the firstillustrates a two-dimensional fix (i.e. two satellite signals are withinrange), the second is a three-dimensional fix (i.e. three satellitesignals are within range), the third represents when the GPS receiver201 is unable to locate any satellite signals and the fourth representswhen the GPS is disabled, for example, when the GPS receiver 201 isdisabled or otherwise un-operational. The four graphics in oneembodiment, are represented by a basic graphic of a satellite, a circlewith two vertical bars attached to the sides of it. When the receiver201 is unable to fix on any satellites or less than two satellites thecircle is unfilled. When there is a two-dimensional fix the circle ispartially filled, with a three-dimensional fix the circle is filled inmore completely. When the GPS receiver 201 is disabled, the circle has a“X” through it. However, the type of graphical display is unrelated tothe function and the graphics may be designed in any manner able tocommunicate to the user the GPS satellite signal information.

A keypad lock icon 419 indicates if the keypad and joystick 207 havebeen locked. If the joystick and keypad are locked the user will not beable to select any functions or activate any features. This feature isactivated when the user holds the cancel button 208 for longer than twoseconds. As discussed above, this insures that the GPS unit 101 will notaccess any functions or send any information if the user accidentallybrushes against a button, or the joystick. The keypad lock 419 is agraphic of a padlock with a keyhole, however the graphic may be anysuitable design. Additionally, the keypad lock icon 419 is not vital tofunctionality and is merely a convenience to the user and may be omittedfrom the LCD screen display 202.

A data TX/RX icon 421 indicates whether the device is transmitting orreceiving NMEA data stings. Also, this icon may be used as atroubleshooting tool. For instance, if the unit is not displaying datafor any other units, the user may see if it is actually receiving theNMEA sentences and not processing it correctly or whether the unit isoutside of the range of the communication device. The graphic for thedata TX/RX icon is a upwards slanted arrow, but may be designed in anymanner.

A time icon 422, in one embodiment illustrates the current time inminutes and hours and additionally whether it is after-noon (p.m.) orbefore noon (a.m.). However, the time icon 422 may be designed toreflect the current time in military format, therefore without a.m. orp.m. displayed, or as an analog clock graphic. Similar to the otherinformational icons, the time icon 422 may be omitted from display ormay be located anywhere on the LCD display 202.

A Log icon 410 indicates to the user that the system is logging allactivities; power on, power tuned off, etc. The log icon serves as anoperational and diagnostic tool by allowing the user to view all therecent activities of the GPS.

A G-mouse 412 icon appears when the unit is connected to either a serialor USB port and is being communicated to by appropriate software. Thisallows the user to know whether he has correctly connected the GPS unitto an external USB connection or serial port and whether it istransmitting and receiving information via the connection.

A backlight indicator icon 413 reflects whether the backlight of the LCDis on. This is important when the user may have selected the backlightto stay on all the time, which increases power consumption (decreasingoperational time of the unit) and where during daytime operations itwould be difficult to see whether the backlight is in fact lit. Thebacklight icon 413 is represented as a square with radiating lines andis located in the lower corner of the LCD display 202. However, it maybe designed as any graphic and may be positioned anywhere on the display202 or may be omitted.

A group people icon 415 allows one to select between various groups andthen either all or one individual in this group. Once a group orindividual has been selected, the user may then choose to have the unitdisplay that group or individual's travel information, such as speed,location, course, altitude, etc. The group people icon 415 is a graphicof the outline of a person's head and shoulders and is located next tothe message icon 416 and the backlight icon. However, it may be designedas an graphical illustration and may be positioned anywhere on thedisplay 202 or may be omitted.

A message icon 416 reflects whether the user has received any newmessages. The message icon 416 is designed as an envelope, but may beany illustrative graphic. In one embodiment, when the user does not haveany new messages the messages icon 416 is not displayed. However, theicon 416 may be designed such that when there are no new messages thegraphic depicts an open envelope or other illustrative design.

A date icon 411 and temperature icon 414 indicate the current date andtemperature. The date 411 is represented as a numerical-alphacombination, but could be represented as purely a numerical display.Additionally, the temperature is represented by a numerical graphic, butcould be represented by any type of graphic such as a thermometer. Also,the temperature icon 414 includes a degree symbol “°” indicating thatthe number represents the temperature. The temperature icon 314 may alsoinclude the units of the numeric reading, the units represented may beFahrenheit, Celsius or Kelvin, represented by “F”, “C” and “K”,respectively.

The functional icons are similar to the informational icons, but in oneembodiment the functional icons are present on the main menu screen andtheir appearance does not depend on the status of the information thatthey reflect. The functional icons allow a user to select certainfunctions of the GPS unit 101. Each functional icon leads the user to amenu hierarchy listing different options.

FIG. 4 a illustrates the menu hierarchy under the main menu shown inFIG. 4, and the functionality available to the user under each icon. Thefunctional icons may include a finder 401, tracks 402, waypoints 403,GPS data 404, compass 405, unit data 406, messaging 407, extras 408,tools icon 409, selection tool (cursor) 424 and a header 423. The header423 displays the name of each icon as the icon is highlighted by theuser. Similar to the informational icons, the functional icons may berepresented by any graphical design and may be positioned on anylocation of the LCD display 202. Additionally, one or more functionalicons may be omitted or more added, depending on the desiredfunctionality. Furthermore, the functional icons may be hidden from themain screen and accessed through other icons or options on the screen.

A finder icon 401 causes the device to display the travel information ofa group of units and/or a particular unit When the user selects thefinder icon 401, he is given a number of options, such as locating aparticular unit within a group, as well as changing the group his unitis currently a member of. The first option displays all members withingroup, and their relationship with the unit and group. The nextinformation displayed is the information for a particular unit. Todisplay this information, the user uses the joystick 207 to select thedesired unit as discussed herein. Once a unit is selected the LCD 202displays the selected unit's information, such as the time the lastinformation from the selected unit was received, the course, groupidentification, user identification, temperature, speed, direction,altitude, location and relative relationship to the unit including theselected unit's distance and bearing with respect to the unit. Alongwith the selected unit's information, the unit displays more optionsallowing the user to plot a course towards unit, track the next locationof the unit or calculate the estimated time of arrival to the unit. Theinformation displayed is the result of calculations of themicroprocessor 302, based on the receipt of one or more of the NMEAsentences from other devices. The finder icon 401 in one embodiment, isdesigned as a binoculars graphic. However, similar to the informationalicons, the graphic display may be any designed suitable to convey theicon's function.

The finder icon 401 additionally allows a unit to query another unit'sinformation. If a unit is queried it transmits the latest travel data tothe querying unit. In order to select a particular unit, the user usesthe joystick 207 to select the group the unit belongs to and then usingthe joystick, highlights the unit's identification number or user name.Once a unit or name has been selected the unit then displays a popupicon indicating that the user has selected a unit to be queried. Oncethe user has acknowledge the selection, the unit then sends out a queryto the selected unit. The query is a hex command requesting thespecified unit to transmit an updated position and other travelinformation.

A tracks icon 402 in one embodiment is illustrated as a magnifyingglass, and the tracking function causes the unit to display differentoptions such as starting, stopping or erasing a track. The user then mayselect the desired option and either start, stop or erase a track. Theunit may store multiple paths traveled by the user. The trackingfunction saves the data points recorded by the GPS receiver 201 as theunit travels. In addition, the microprocessor calculates and the LCDdisplays the duration of the track, start and stop time, distancecovered, maximum speed, average speed, number of waypoints stored andmarked. The tracks may be saved via the internal circuitry of the GPSunit 101 and also be downloaded to a computer or other device along withother information, through a direct or wireless connection. Whendownloaded onto a computer, personal digital assistant or other device,mapping software may be used such that the user may see his path on anytype of map. Also, the tracking information, including the text may betransmitted to other units.

A waypoints icon 403 causes the unit to display different options suchadd, view, save or delete waypoints as well as reading receivedwaypoints, setting a course to a received waypoint, and sending storeduser waypoints to other units. The waypoints icon 403 may be designed asany graphic, but in one embodiment is designed as a flag. The waypointsfunction causes the unit to display a map or coordinates, allowing auser to select each waypoint or meeting point for other users mymanipulating the joystick. In addition to marking the coordinates of thewaypoint, the unit allows a user to annotate the name and points ofinterest and assign to the waypoint an icon from a pre-stored symbollibrary stored in the unit's memory. The icons may be uploaded, changed,deleted and created as desired and may be any type of graphicalillustration, such as a depiction of a tree, human body (for search andrescue), mountain, lake, etc.

To create a waypoint, the user moves the cursor to “add a waypoint”,where he may correct the elevation, change the waypoint name, change theicon assigned to the waypoint and stores the waypoint onto the unit'smemory. If a waypoint is to be set as a meeting point, the user simplyaccesses the same menu, selects from the stored waypoint list thewaypoint that needs to be transmitted, and then sends it to the entiregroup or a particular unit of a selected group by using the joystick207. Additionally, the user may select the view option, causing the unitto display other unit's waypoints that have been sent to it or deleteprevious waypoints. The waypoints function allows for users to moreefficiently communicate meeting locations and may be used to moreefficiently perform safety tasks. For example, users participating insearch and rescue missions may easily inform the others of what areasthey have searched and if there is anything interesting or helpful atcertain locations.

A GPS information icon 404 in one embodiment is a graphic of a satelliterevolving Earth. The GPS information function causes the unit to displayits current location, time and date, travel speed and the GPS fix. TheGPS fix displays on the unit whether there is a two or three dimensionalsatellite fix. The more satellites the GPS receiver 201 has a fix on themore accurate the location information will be, therefore the user mayalter his position to receive a better fix. For example, if he islocated under a tree or other obstruction the antenna may not be able toreceive as many signals. The signal strength is detected by the GPSreceiver 201 and is based on the strength of each satellite signal.Additionally, the satellite signal strength function allows a user tosee if the unit has both WAAS and GPS satellite information, allowinghim to estimate the precision of the location data provided by the GPSunit 101. The GPS information icon may be used prior to the start of asearch and rescue operation to ensure that the unit is receivingsatellite positional signals and thus GPS coordinates.

A compass icon 405, when selected causes the unit to display its currentbearing and direction. The compass icon 405 in one embodiment is anillustration of an analog compass. The compass displayed on the LCDscreen 202, once the user has selected the icon 405, includes a circlewith North, South, West and East directions and an arrow that pointstowards the direction the GPS unit 101 is facing. The graphical displayof the compass may be altered to any type of design, such that symbolssuch as NW, SE, etc. may represent to the user the direction of the GPSunit 101, or a more detailed display such as the actual number ofdegrees off North that the GPS unit 101 is facing. The direction of thearrow or the number of degrees displayed is determined by themicroprocessor 302 based on the electronic signals sent from the compass301. Additionally, the compass icon 405 displays a compass calibrationoption. If the user selects this option the unit will calibrate thecompass by using a known reference location. A group list icon 406 is agraphic illustration of a GPS unit, and causes the unit to displayoptions such as select a unit or group. If a specific unit is selected,the unit will display the unit's tracks, location, temperature,altitude, heading and speed. Additionally, the group list icon willdisplay the relationship the unit has in terms of bearing and directionwith the selected unit. If the user selects a group the unit displaysthe group's individual identification names, date the last update wasreceived, and location, temperature, speed, direction, elevation of thegroup's units and its relationship to all units.

Additionally, the user may select to poll remote units to update data.This function operates in the same manner as a query and updates thegroup information displayed. The microprocessor sends a request, in theform of a hex command, to each unit via the communication device 100asking the selected units to send their travel information. The hexcommand includes a “$” character indicating the beginning of thecommand. However, unlike the NMEA sentences it does not include atransmission type, but rather a string of hex digits. The “$” characteralerts the microprocessor that it is receiving a data string and themicroprocessor then decodes the data following the dollar-sign characterin a manner similar to the NMEA sentences, discussed above. Followingthe $ and hex digits is a carriage return and sentence delimiter. Thecarriage return and sentence delimiter indicate to the microprocessorthe end of the hex command. The basic format of the hex command is:$<CMD></CMD><CR><LF>. The command data fields, <CMD> and </CMD> mayinclude any number of hex digits and allows the unit to request datastrings, in the form of NMEA sentences and other transmissions, fromother units. The unit being queried, after receiving the request, inturn transmits the third NMEA sentence discussed above. The third NMEAsentence includes the unit's position, location, speed, altitude, andother travel information about the specific unit. Once the data isreceived the unit requesting the information stores it in its memory.

A unit data icon 406 shows the user his or her pertinent operationaldata. For example, the time and date, location, speed, course, maximumspeed, average speed and distance traveled. The microprocessorcalculates the maximum and average speed as well as the distancedtraveled and this information along with the course and distancetraveled is stored in the memory 304. The memory 304 stores eachposition calculated throughout the entire course, that information isthen easily displayed to the user via the unit data function.

A messaging icon 407 is an illustration of an envelope and when selectedcauses the unit to send and receive text messages. If the user choosesto send a text message, the unit displays a message composition screenon the LCD display 202. The message composition screen is illustrated inFIG. 4 b. A virtual keyboard 425 appears below a message compositionarea 424 allowing the user to select different text characters tocompose his message. The virtual keyboard 425 allows a user to selectdifferent characters by maneuvering the joystick 207, a stylus, fingeror other object to different. Once the message has been composed, theunit displays a request to confirm that the message is ready to be sent.After the user has confirmed that the message is ready to be sent, theunit displays a screen requesting the user to determine whether themessage should be transmitted to all units within a particular group oronly to a specific unit.

If the unit has received a message, the informational message icon isdisplayed on the LCD main screen alerting the user that a message hasbeen received. The user may then select the read messages option, oncethe option has been selected, the unit to displays a mailbox includingall new and previous messages. The user may then select which messageshe wishes to read by using the joystick 207 to maneuver betweenmessages. The read message screen is then displayed, displaying thesender's identification name as well as the message. Finally, the unitdisplays an option to reply to the new message. The user may then choosethe reply option, which causes the unit to display the messagecomposition screen.

An extras icon 408 allows for a user to enter in information. Forexample, agency or departmental data, such as telephone numbers, radiofrequencies etc. The information is stored in the memory, but accessedthrough the extras function. The extras icon 408 is 408 represented bybriefcase graphic. Additionally, a calendar is included under the extrasicon 408. The calendar is a standard monthly calendar illustrating thecurrent day and may be view by week, month or day. The extras functionmay be easily modify to include other standard information by connectingthe unit to a PC or laptop and using the utilities icon.

A tools icon 409 may be represented by a graphical depiction of ascrewdriver and wrench. The tools function is the system setup utilityand causes the device to display a variety of settings options of theGPS unit 101. The settings displayed are user name, time zone, time anddate format, unit display contrast, unit position format and map datumformat, measurement for distance and speed (miles per hour, kilometersper hour, etc.), temperature units (Celsius, Fahrenheit, Kelvin),elevation units (feet, meters, yards or other measurement unit), GPSstartup, unit power management, language, power up log, G-Mouse on/off,RX mute, SOS timer, baud rate, as well as logged system information tothe user such as but not limited to: battery voltage, stored waypointsand tracks, and memory percentage used. For example, the user may changehis identification name or group membership. However, in one embodiment,the user may only view his hardware identification name and not modifyit. If the SOS setting is selected the GPS unit 101 will transmit itslocation and user identification at timed intervals. This intervals inone embodiment range between two seconds and 99 minutes.

The G-Mouse on/off option allows the user to transmit information viathe USB UART to a personal computer, modem or other device through thedevice's USB port or serial port. The RX Mute turns on and off thetrailing edge of the audible transmission. This silences the audiblenoise of the FFSK data burst, so that the user does not hear ittransmitted, while still allowing the device to transmit it. The, BaudRate allows a user to select the serial port speed, for instance between9600, 4800, 19200 and 38400 baud. The logged system information displayson the unit the number of times that the unit was power up, its externaltemperature, the estimated battery power remaining, the number of storedwaypoints and tracks and the percentage of the memory used.

A selection tool icon 424 may be represented by an outline of a squareand the display indicates the icon that the joystick 207 is currentlyable to select. This allows the user to be able to knowingly select thecorrect functions. The selection tool 424 may be any sort of graphic orindicator. For example, the selection tool may simply be an animation ofthe icon it is highlighting, circular, rectangular or any other shape,or may cause the functional icon it is selecting to change colors. Thedisplay of the selection tool 424 is not related to the functionality ofthe GPS unit 101 and is simply a tool making it easier for the user toaccess different functions of the unit 101.

FIG. 5 illustrates multiple GPS units 101 each connected tocommunication device 100. The GPS units 101 transmit and receive signalsvia the communication devices 100. In this example, the communicationdevices are two-way radios and transmit the signals to each otherthrough radio waves, digital or analog. As discussed with respect FIG.1, the GPS unit and two-way radio are connected to each other through asignal cable. The signal cable enables the GPS unit to send and receivesignals from the two-way radio. The two-way radios transmit wavesthrough the atmosphere until reaching other two-way radios.Additionally, the field GPS units 101 communicate to a computer basestation 500 and a field computer 500, there may be more base stationsincluded, however in FIG. 5 only two base stations are depicted. Thebase stations 500 may be placed in the field along with the GPS units101 and communicate via radio waves or the base station may be locatedaway from the field and communicate with the units 101 through aninternet or cellular connection. For example, the base station 500 mayconnect to the unit through a USB, serial connection or wirelessconnection. For example, in one embodiment a communication device isconnected to a GPS unit and the GPS unit is connected to the basestation via the USB port of the base station 500. In another embodiment,the base station includes a radio transceiver externally located, suchas on the top of a building. This radio transceiver receives radiotransmissions on the selected channel and then supplies them to the GPSunit connected via to the USB port of the base station. The USB outputthen transmits information from the GPS unit 101 to the base station500. This allows the base station 500 to display all units and theircurrent location and other travel information. Once connected, the basestation 500 computer may include mapping software such as GOOGLE EARTHor TERRALOOK and the base station user may track in real time, thepositions, speed, temperature, altitude, and all other relevantinformation of all users. Additionally, the base station 500 may polleach user in the field to automatically receive updates to moreaccurately track their locations in real time. The base station 500 mayalso send text messages to the other users and has the same capabilitiesas each user, therefore may receive, track and store information andsend messages to each unit

FIG. 6 illustrates multiple GPS units 601, 603 connected to cell phones600, 602. The GPS units 601, 603 in this embodiment communicate witheach other through cell phones 600,602. The cell phones 600, 602transmit signals on a cellular network, using cell towers 604 to reflectthe signals almost anywhere. In this embodiment the GPS units 601, 603may be located on different continents and as long as there is acellular network in both locations, the GPS units 601, 603 may send andreceive data from each other. The first cell phone 600 receives a signalfrom the first GPS unit 601 and transmits the signal to the first celltower 604 which then sends the signal to other cell towers until itreaches the second cell phone 602. The second cell phone 602 thencommunicates the signal to the second GPS unit 603 via the connectioncable 109.

FIG. 7 illustrates multiple GPS units 701, 703, 705 connected tocommunication devices 702, 704, 706 transmitting and receiving signalsto each other, a base station computer 707 with a digital transceiver,and to a field computer 710 connected to a two-way radio 708 and GPSunit 709. Using the group list function, each GPS unit sees its positionrelative to the other units. For example, user of the first GPS unit 701sees himself, displayed on the LCD screen, located south-west relativeto the other users of second and third GPS units 703, 705. User of thesecond GPS unit 703 is able to see that he is located north of the otherusers. User of the third GPS unit 705 is able to notice that he islocated south of second user 703 and east of the first user 701. Theuser of the field computer 710 is able to view his location as northwestof the other users. In addition to viewing his position on his GPS unit709, he is able to view his position on the computer 710. Additionally,each user may view the name of each other user as well as the hardwareidentification of each unit. The base station 707 and field computer 710are able to see the position of each user not only relative to eachother, but also overlaid on a map depicting the actual location of eachuser. The real-time tracking is performed by the computer by using theactual GPS coordinates of each user loaded into mapping software. Thebase station 707, field computer 710 and individual users may alsoscreen which users are illustrated on their units. For instance, user ofthe first GPS unit 701 may wish only to view user of the second GPS unit703, in that case the display would only illustrate that he was locatedbehind the second GPS unit 703.

All directional references (e.g. upper, lower, upward, downward, left,right, leftward, rightward, top, bottom, above, below, inner, outer,vertical, horizontal, clockwise and counterclockwise) are only used foridentification purposes to aid the reader's understanding of examples ofthe invention, and do not create limitations, particularly as toposition, orientation, or use of the invention unless specifically setforth in the claims. Joinder references (e.g. attached, coupled,connected, joined and the like) are to be construed broadly and mayinclude intermediate members between a connection of elements andrelative movement between elements. As such, joinder references do notnecessarily infer that two elements are directly connected and in afixed relation to each other.

Although the present invention has been described with respect toparticular apparatuses, configurations, components, systems and methodsof operation, it will be appreciated by those of ordinary skill in theart upon reading this disclosure that certain changes or modificationsto the embodiments and/or their operations, as described herein, may bemade without departing from the spirit or scope of the invention.Accordingly, the proper scope of the invention is defined by theappended claims. The various embodiments, operations, components andconfigurations disclosed herein are generally examples rather thanlimiting in scope.

1. A method of communicating between a plurality of navigation devicescomprising: obtaining positional information for a first navigationdevice by assessing a plurality of global positioning satellite signals;generating a data signal for transmission to a plurality of otherdevices, the data signal including a latitude value obtained from thepositional information for the first navigation device, a longitudevalue obtained from the positional information for the first navigationdevice, and an identification of the first navigation device;transmitting the data signal to a communication device through a signalcable, wherein the communication device is separate from the firstnavigation device; and transmitting the data signal, utilizing thecommunication device, to a plurality of other navigation devices suchthat each of the plurality of navigation devices can identify anddisplay a geographic position of the first navigation device.
 2. Themethod of claim 1 wherein the data signal further comprises a textmessage.
 3. The method of claim 1 wherein the data signal furthercomprises: a course bearing; an altitude value; a speed value; and awaypoint name.
 4. The method of claim 1 wherein the data signal is aNational Marine Electronics Association (NMEA) signal, the NMEA signalincludes 82 characters, wherein: character 1 is a dollar sign,characters 2 through 6 is a transmission type, characters 7 through 8 isa latitude degree, character 9 is a period, characters 10 through 14 islatitude minutes, character 15 is a latitude direction, characters 16through 18 is a longitude degree, character 19 is a period, characters20 through 24 are longitude minutes, characters 25 is a latitudedirection, characters 26 through 35 are a waypoint name, characters 36through 37 is an ICON index value, characters 38 through 40 is analtitude measurement, characters 41 through 46 is a SCODE value,characters 47 through 48 is a group identification, characters 49through 54 is a date, characters 55 through 60 is a time reading,character 61 is an asterisk, and characters 62 through 82 are a checksumand sentence delimiter.
 5. The method of claim 1 wherein the data signalis a National Marine Electronics (NMEA) signal, the NMEA signal includes82 characters, wherein: character 1 is a dollar sign, characters 2through 6 is a transmission type, characters 7 through 46 is a textmessage, characters 47 through 56 is a name identification, characters57 through 62 is a SCODE value, characters 63 through 64 is groupidentification, characters 65 through 66 is a status value, characters67 through 68 is a ICON value; character 69 is an asterisk, andcharacters 69 through 82 are a checksum and sentence delimiter.
 6. Themethod of claim 1 wherein the data signal is a National MarineElectronics (NMEA) signal, the NMEA signal includes 82 characters,wherein: character 1 is a dollar sign, characters 2 through 6 is atransmission type, character 7 is a fix status, characters 8 through 9is a latitude degree, character 10 is a period, characters 11 through 15is latitude minutes, character 16 is a latitude direction, characters 17through 19 is a longitude degree, character 20 is a period, characters21 through 25 are longitude minutes, characters 26 is a latitudedirection, characters 27 through 29 is an altitude value, characters 30through 32 is a course bearing value, characters 33 through 34 is aspeed value, characters 35 through 44 is a name identification,characters 45 through 50 is a SCODE value, characters 51 through 52 is agroup identification, characters 53 through 54 is a status value,characters 55 through 56 is a ICON value, characters 57 through 62 is adate value, characters 63 through 68 is a time value, character 69 is anasterisk, and characters 69 through 82 are a checksum and sentencedelimiter.